1. Technical Field
This invention relates to copper alloy, and more particularly, to a copper alloy which is suitable for a commutator of a DC motor used for an alcohol-containing fuel supply pump.
A fuel supply pump is broadly used for supplying fuel to an engine in many kinds of vehicles, such as automobiles. Such fuel supply pump comprises a pump portion for supplying fuel to the engine and a motor portion for driving the pump portion. The motor portion usually comprises a DC motor and a commutator by which the motor is driven by a DC power supply. Conventionally, silver containing copper alloys are used for such a commutator, because such copper alloys prevent the commutator from being softened by the heat of a molding resin which covers the commutator.
As a fuel for automobiles, gasoline or light oil has been used. Recently, however, in view of concerted efforts to prevent global environmental pollution, alcohol-containing fuels are proposed to be used for cleaning up automobile exhaust gases. When the conventional copper alloys are used for a commutator of a DC motor used in such an alcohol-containing fuel, however, there is a disadvantage in that the commutator, which is made of a silver-containing copper alloy, is corroded, because alcohol is more corrosive than the conventional gasoline or light oil, thereby resulting in deteriorating the durability of the motor.
2. Disclosure of the Invention
Accordingly, it is an object of the invention to provide a copper alloy which is not corroded in an alcohol-containing medium.
It is a further object of the invention to provide a commutator for a motor in which the abrasive resistance characteristics in an alcohol-containing medium are improved.
It is a still further object of the invention to provide a motor in which the durability in an alcohol-containing medium is improved.
According to the first feature of the invention, a copper alloy consists essentially of:
0.5 to 8 weight percent tin or nickel alone or in combination, 0.02 to 0.15 weight percent zirconium, and the remainder weight percent copper; the zirconium being dispersed in the copper alloy as precipitates. PA1 0.5 to 8 weight percent tin or nickel alone or in combination, 0.02 to 0.15 weight percent zirconium, and the remainder weight percent copper; the zirconium being dispersed in the copper alloy as precipitates. PA1 a pump portion for supplying the medium; and PA1 a motor portion for driving the pump portion; the motor portion comprising a DC motor and a commutator, the commutator made of a copper alloy which consists essentially of: PA1 0.5 to 8 weight percent tin or nickel alone or in combination, 0.02 to 0.15 weight percent zirconium, and the remainder weight percent copper; the zirconium being dispersed in the copper alloy as precipitates.
According to the second feature of the invention, a commutator for a motor made of a copper alloy, the copper alloy consisting essentially of:
According to the third feature of the invention, a motor for supplying a medium pump which comprises: